One of two principles of heredity first formulated by Gregor Mendel, founded on his experiments with pea plants and stating that the members of a pair of homologous chromosomes segregate during meiosis and are distributed to different gametes. Also called law of segregation.

The second of these two principles, stating that each member of a pair of homologous chromosomes segregates during meiosis independently of the members of other pairs, so that alleles carried on different chromosomes are distributed randomly to the gametes. Also called law of independent assortment.

(měn'dlz) Any of the principles first proposed by Gregor Mendel to describe the inheritance of traits passed from one generation to the next. ◇ Mendel's first law (also called the law of segregation) states that during the formation of reproductive cells (gametes), pairs of hereditary factors (genes) for a specific trait separate so that offspring receive one factor from each parent. ◇ Mendel's second law (also called the law of independent assortment) states that chance determines which factor for a particular trait is inherited. ◇ Mendel's third law (also called the law of dominance) states that one of the factors for a pair of inherited traits will be dominant and the other recessive, unless both factors are recessive. See more at inheritance.